As a result of population growth and aging of the population it is estimated that there will be a shortfall of 35,000-52,000 adult primary care physicians by 2025 as the Affordable Care Act (ACA) further increases demand for health care. One solution to the anticipated shortage is enacting full practice authority regarding scope of practice (SOP) for advanced practice nurses (APRNs) and in particular, for certified nurse midwives (CNMs) thereby allowing them to practice to the full extent of their training with limited or no physician oversight. When comparing CNM to physician care, CNM groups have been shown to have lower rates of poor outcomes such as episiotomy, Cesarean delivery, epidural and other analgesia use, perineal lacerations, and neonatal intensive care unit admission as well as higher rates of favorable outcomes. Past research has focused on quality of care between provider types but has not linked SOP laws directly to health outcomes. A better understanding of the role of expanded SOP laws is needed to guide state and federal policies. The overall goal of this project is to use the `natural experiment' that occurs as states change their laws affecting SOP for CNMs over the 1994-2012 time period to evaluate the effect of these changes on the CNM supply and practice and in turn, maternal and infant outcomes. Twenty-four states made at least one change to their SOP laws to move from a more restrictive to less restrictive practice environment for CNMs over the study period. We propose to evaluate the effects of these expansions on: 1) Altering the labor market for CNMs; 2) Encouraging substitution between physician and CNM services; 3) Improving maternal behaviors and birth outcomes; and 4) Lowering total health care costs for births. By linking data on the SOP laws for all fifty states for 1994-2012 from The Nurse Practitioner to data from the National Vital Statistics System Birth Certificates from each state and year we will be able to examine the effects of the wide variation in state activities observed over this period. We will use a quasi-experimental study design to test the mechanisms through which changes in the SOP laws could affect maternal and infant outcomes and in turn, test the strength of these mechanisms in affecting health outcomes at delivery. Using a difference-in-difference (DID) methodology, which allows for a comparison within a state before and after the law changes, while netting out similar trends in states that do not experience law changes, and capitalizing on the experiment of prior state changes in SOP laws, we can shed valuable insight on the role that full practice authority versus more restrictive SOP laws plays in securing a supply of primary care providers that could maintain or improve maternal and infant outcomes at the same or lower costs.